PURPOSE: To determine a shearing position, by periodically detecting an image made up by a plate material by means of a primary image sensor provided with a light receiving element disposed along the direction of the plate width and discriminating whether the plate material edge is in irregular form.
CONSTITUTION: A bar of a light source 20 is disposed beneath a steel plate 10 to be conveyed and a back-light is radiated. At the topside of a plate conveying passageway, for example, a 2048 bit one-dimensional image sensor 22 and a signal processor 24 are set up. According to the irregular form in a steel plate edge part, a pulse signal is outputted, whereby, inside a computer 36 outputting command to a shearing position 29 with the desired timing, the edge shearing position is determined from edge form information obtained by a set of edge data being astride both sides of a solid image pickup element at the address of 1024 of the sensor 22 corresponding breadthwise to the central position.
SATOU KAZUHIKO
TSUKUDA HIFUMI
KONISHI TOSHIHIRO
TAI HIDEKAZU
